This invention is concerned with a system for locating and monitoring the status of a number of individuals located in a particular area, and communication of information in a robust manner to locations throughout the area.
The present invention is particularly suited to monitoring and/or locating entities, be they human, animal, or machine, operating alone or in groups in hazardous or isolated environments. However, while the present invention will be described in the context of its use in a hazardous area, being an underground mine, it also finds application in any situation where it is required to monitor the status of individuals remotely.
Mine communication systems providing routine voice, data and video information rely on a mine-wide high density communication pathway. Such systems require a sophisticated network which may not survive a catastrophic event such as an explosion or mine collapse.
There is a need for a reliable and extensible modular network which identifies the location of all personnel and their status at all times, even in the event of a serious incident.
Various individual monitoring systems have been described in the prior art.
For example, U.S. Pat. No. 4,709,330 describes a system for supervising and guiding workers at various locations, the system including a number of receivers arranged in a number of sections of a construction site for receiving infrared radiation emitted by workers to produce a detection signal which is sent on to a control room for processing. Canadian Patent application 2,018,109 describes a locater system for use in underground mining comprising a locater transmitter to be carried by the person to be located and a locater receiver to be carried by the searching person. However, none, of these prior art systems provide a relatively low cost and reliable system for monitoring the location and status of a number of personnel, or machine work-units, in a hazardous environment, nor do they provide a system in which collected information is available at locations throughout an area.
An object of the present invention is to provide a locating and monitoring system that alleviates, at least in part, one or more of the problems attending prior art systems. In particular, it is an object of the present invention to provide a reliable and robust system for determining the location and status of a number of individuals in an area or site, particularly in hazardous environments.
According to a first aspect the invention broadly provides a system for locating a mobile entity in an area including:
a) a network of fixed communication beacons for relaying messages, said fixed beacons arranged in predetermined locations;
b) a mobile communication beacon adapted to be attached to the entity to be located and for transmitting mobile messages, said mobile messages being coded to uniquely identify the message and to uniquely identify the mobile communication beacon;
the beacons being arranged so that operatively, the mobile communication beacon transmits said mobile messages to at least one fixed communication beacon of the network located in its vicinity, said at least one beacon modifying said message by appending a unique beacon identifier and transmitting the modified message to adjacent beacons for transmission throughout the beacon network so that the identity of the at least one fixed communication beacon which first modified the message is stored at each fixed beacon throughout the network.
According to a further aspect the present invention broadly provides a method for locating a mobile entity in an area containing a network of beacons, including fixed communication beacons and mobile communication beacons, said fixed beacons being located at recorded positions, said mobile entity being fitted with a mobile communication beacon, said method including the steps of:
a) transmitting from the mobile communication beacon a unique message, including data identifying said beacon, to a first one of said fixed communication beacons in the vicinity of said mobile beacon;
b) appending to said message a unique identifier associated with the first at least one fixed communication beacon, thereby forming a modified message;
c) repeatedly transmitting the modified message from communication beacon to adjacent beacons and storing details of the modified message, including the identity of the beacon which created the modified message at beacons throughout the network;
d) interrogating a beacon to determine the identity of the beacon which created the modified message in order to determine the vicinity of the mobile communication beacon at the time the unique message was transmitted.
Preferably, the present invention provides, a system for determining the approximate location of each one of a plurality of mobile entities located in an area, the system including:
a plurality of mobile beacons adapted to be worn or carried by each individual and being capable of generating a signal containing an identifier;
a network of at least two fixed beacons located throughout the operating area, each fixed beacon being capable of transmitting a signal and of receiving the signal generated by at least one mobile beacon and the signal generated by at least one other fixed beacon;
means by which the transmitted information may be self-routed to the beacons in the network where it may be stored or interrogated;
means by which the location of the mobile-beacons can be determined, stored and available from at least one other beacon; and
a control or monitoring means capable of receiving the signal generated by at least one fixed beacon and therefrom providing an output indicative of the location of each said entity.
Preferably the invention provides a system for determining the approximate location of each one of a plurality of mobile entities located in an area and for monitoring at least operational parameter of each of said entitles, the system including:
a plurality of mobile beacons adapted to be worn or carried by each individual and being capable of generating a signal containing an identifier and data indicative of the at least one monitored vital sign, each transmitter being associated with a respective sensor capable of monitoring at least one vital sign of the entity wearing or carrying the transmitter;
a network of at least two fixed beacons located throughout the operating area, each fixed beacon being capable of transmitting a signal and of receiving the signal generated by at least one mobile beacon and the signal generated by at least one other fixed beacon;
means by which the transmitted information may be self-routed to the beacons in the network where it may be stored or interrogated;
means by which the location and the status of the entities associated with the mobile beacons can be determined, stored and available from at least one fixed beacon; and
a control or monitoring means capable of receiving the signal generated by at least one fixed beacon and therefrom providing an output indicative of the location and status of each said entity.
The beacons transmit a signal which is preferably a short range RF signal The beacons, which may be fixed or mobile, preferably transmit at intervals a low-power short duration radio message, including an identification and status signal. Preferably the beacons used are functionally identical whether they be fixed or mobile.
A mobile beacon may be carried or worn by an entity in the area to be monitored. Such an entity will most frequently be a human worker but could also be an animal or mobile machine-unit, for example a mine robot. In the case of a human worker the mobile beacon may be conveniently integrated with an article of clothing such as headgear or footwear. For example the beacon may be integrated with the miner""s lamp and battery pack. The mobile transmitter may be self-activated when the lamp is removed from the charger rack prior to a mine worker commencing a work-shift. Preferably the mobile transmitter is capable of self-verifying normal operation. The mobile beacon may include means for allowing the wearer to transmit pre-coded messages to the control or monitoring means thereby allowing the wearer to convey information on his or other""s status during an emergency. Preferably the beacons are coupled to at least one sensor.
Preferably the sensor, or sensors, to which a moble beacon is coupled is capable of monitoring a characteristic indicative of the operational status of the entity with which it is associated. Accordingly when worn by a human worker it is desirable that the sensor be capable of monitoring the wearer""s respiration or pulse. Alternatively, by sensing the attitude of the wearer, it is possible to determine whether he or she is standing or lying which in turn may indicate whether the wearer is conscious or not.
The sensor may be sensitive to movement or vibration. Preferably the sensor is capable of measuring minute movement or some other physical parameter without the use of probes requiring penetration of the skin. The sensor may be a transducer, including piezoelectric, electromagnetic and resistive transducers. However, more preferably the sensor requires no transducer connection to the skin and may be a seismometer, accelerometer, or geophone adapted to detect chest wall movement or some other physical movement of the wearer. Alternatively the inventors have reported considerable success in determining the pulse of a wearer by means of conductivity loops sensitive to the depolarisation signals of the heart.
The sensor may be incorporated into the clothing, footwear or headgear of the individual. It may be incorporated into an expandable chest band that can be comfortably worn around the chest, or carried in the battery belt or battery pack, the device detecting chest expansion and contraction during breathing.
The sensor may be connected to the mobile beacon by a hardwired connection or it may communicate with the mobile transmitter by a wireless signal such as an infrared or RF signal.
The fixed beacons are located at intervals over the active area such that each beacon can receive the transmitted signal of at least one other. The fixed beacons are capable of both transmitting and receiving signals and have identity and message passing capability. Each beacon is capable of receiving a signal containing identification (of another beacon) and status information from mobile beacon and is further capable of packaging both personnel and network identification and status information into a message signal. Status information may include information derived from at least one environmental sensor coupled to said fixed beacon, for example information regarding the local dust concentration, temperature or availability of cabled power.
In order that the invention may be more readily understood, the invention will now be described in reference to the following non-limiting embodiment.